The present invention generally relates to control systems for automotive vehicles, and more particularly relates to an integrated control of an active steering system and a brake system of an automotive vehicle for improving upon a handling, stability, and a maneuverability of the automotive vehicle.
Some automotive vehicles known in the art utilize an active brake control to enhance a directional stability of the vehicle at or close to a limit of adhesion. Some other automotive vehicles known in the art utilize a limited active control of a rear tire steering angle in order to improve a vehicle handling and maneuverability at low speeds. More recently, automotive vehicles are utilizing a limited active control of a front tire steering angle to introduce a steering correction to a steering angle commanded by a vehicle driver in an effort to improve a vehicle directional stability. The present invention addresses a need for an integrated control of vehicle brakes, and a front tire steering angle and/or a rear tire steering angle.
One form of the present invention is an integrated active steering and braking control method for a vehicle. First, a first corrective yaw moment for the vehicle as a function of a steering angle of an axle of the vehicle is determined, and a second corrective yaw moment for the vehicle as a function of a speed differential between a first tire and a second tire of the vehicle is determined. Second, a corrective steering signal is provided to a steering system of the vehicle whereby the first corrective yaw moment is applied to the vehicle, and a corrective braking signal is provided to a braking system of the vehicle whereby the second corrective yaw moment is applied to the vehicle.
A second form of the present invention is also an integrated active steering and braking control method for a vehicle. First, a desired speed differential between the speed of the first tire and the speed of the second tire is determined. Second, a desired steering angle of the axle as a function of said desired speed differential is determined.
A third form of the present invention is also an integrated active steering and braking control method for a vehicle. First, a feedforward portion of a corrective front steering angle signal in response to a plurality of operational signals indicative of an operational state of the vehicle is determined. Second, a feedforward portion of a corrective rear steering angle signal in response to said plurality of operational signals.
A fourth form of the present invention is also an integrated active steering and braking control system for a vehicle comprising a first controller and a second controller. The first controller is operable to determine a first corrective yaw moment for the vehicle as a function of a steering angle of an axle of the vehicle, and to determine a second corrective yaw moment for the vehicle as a function of a speed differential between a first tire and a second tire of the vehicle. The second controller is operable to provide a corrective steering signal to a steering system of the vehicle whereby the first corrective yaw moment is applied to the vehicle, and to provide a corrective braking signal to a braking system of the vehicle whereby the second corrective yaw moment is applied to the vehicle.
A fifth form of the present invention is also an integrated active steering and braking control system for a vehicle. The system comprises a means for determining a feedforward portion of a corrective front steering angle signal in response to a plurality of operational signals indicative of an operational state of the vehicle. The system further comprises a means for determining a feedforward portion of a corrective rear steering angle signal in response to said plurality of operational signals.
A sixth form of the present invention is a vehicle comprising an axle, a first tire, a second tire, and an integrated active steering and braking control system. The system is operable to determine a desired speed differential between a speed of the first tire and a speed of the second tire and to determine a desired steering angle of the axle as a function of the desired speed differential.
The foregoing forms, and other forms, features and advantages of the present invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the present invention rather than limiting, the scope of the present invention being defined by the appended claims and equivalents thereof.